Muffler construction



Oct. 14, 1930. R. s. BLAIR 1,778,016

MUFFLER CONSTRUCTION Filed May 29, 1924 INVENTOR WIBZMI Patented Oct. 14, 1930 PATENT OFFICE ROBERT S. BLAIR, OF STAMFORD, CONNECTICUT' MUFFLER CONSTRUCTION Application filed May 29,

This invention relates to construction for mufflers for internal combustion engines.

One of the objects of the invention is to provide a construction of the above nature, practical and efficient and capable of meeting the requirements of use in a highly satisfactory manner. Another object is to provide a construction of the above nature adapted to operate dependably at all times to muffle the 11o sound of the exhaust explosions from the engine. Another object is to provide such a muffler compact and simple in construction and inexpensive. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter 1 described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing in which are shown one or more various possible embodiments of the several features of this invention,

Figure 1 is a sectional view of a muffler.

Figure 2 is a sectional view of a modified form.

Figure 3 is an upward plan view of another modification.

Figure 4 is a front elevation of the modification shown in Fig. 2.

Similar reference characters refer to similar parts in the several views of the drawing.

Referring now to the drawing in detail, and first to Figure 1, there is shown the rear end portion of an exhaust pipe of an internal combustion engine, for example, the engine of an automobile. The end of this exhaust pipe 10 opensintoachamber 11 formed by a casing 12. The exhaust pipe 10 extends into this chamber 11 to a substantial distance and the chamber, as will be seen, comprises a passage which leads from the end of the exhaust pipe preferably in substantially a circular path back about the end portion of the pipe. In front of the end 10 of the pipe and also at the rear thereof, the chamber is enlarged as indicated at 11 and 11 respectively. The

1924. Serial No. 716,615.

exhaust gases therefore being expelled rapids ly from the end of the exhaust pipe creates an ejector action which tends to reduce the pressure in the portion 11 of the passage. The passage or chamber 11 is provided with a discharge opening 13 through the casing 12, this discharge opening being preferably at substantially the same distance in either direction fromthe end 10 of-the exhaust" pipe.

The exhaust gases discharged from the end of the pipe 10 are projected throughthe portion 11 of the chamber and upon reaching the discharge opening 13, tend to pass outwardly therethrough to the atmosphere. As has been described, the ejector action reduces the pressure in the portion 11 of the chamber, preferably so that the pressure at this portion is substantially below atmosphere. There is thus a tendency to divert a portion of the gases tending to discharge through the exit opening 13 and to draw these gases through the portion 11 back about the end of the exhaust pipe 10.

The explosions of the engine discharge through the exhaust pipe 10 a rapid succession of discharges or puffs of exhaust gases. At each explosion of a cylinder of the engine, a large volume of gas is rapidly forced through the exhaust pipe. Between the successive explosions, there is an interval when the volume of gas discharging from the pipe 10 is far less than thevolume discharged at the instant of each explosion. Considering now one of these puffs of a large volume of gas, this gas passes rapidly through the portion 11 of the chamber and tends to pass out at the discharge opening 13. The ejector action, above described, tends to prevent such exit. drawing a portion of the puff through the portion 11 of the chamber. The extent of the ejector action and the size of the discharge opening 13 may be so proportioned that this diverted portion of the puff of gas, after traversing the portion 11 of the chamber, follows the main body of the puff through the portion 11 and out through the exit 13 in the interval between this puff and the next succeeding puff. The action just described 7 muffled tends, in effect, to create a balance of pressure between the inside of the casing and the outer air. With the parts properly constructed and proportioned, there may thus be had a substantially constant flow of exhaust gases through the discharge opening 13 and the noise of the exhaust is thereby eliectually Referring now to Figure 52, there is shown a modified form of this inuflier. The exhaust pipe 10 from the engi'nec'ylinders' "projects into an enlarged opening 15 in acasiiig 16 which comprises a chamber 17 closed except for the opening 15 about theexhaust pipe 10. The walls of the chamber 17 are'pr'efer'-' ablyjcuryed substantially'asshoivn and the gasesidischarge'd thereinto from the pipelO tendj-topwirlj around therein, as indicated by thearrowsj, The rapid discharge of gases from-the .end 10 of the exhaust pipe creates an ejector action which tends to drawn-air,

intoflthechamber 1? through thepassage 15. y

' the features of this invention and attains theobjects thereof and that At reachexplosion of the engine a puff coinpris ngia large volume of gases is discharged into the chamber 17. The ejector action;

exit ofa por tends to prevent'the immediate tion of this gas througl the discharge passage 15. During the interval, however, be tween-this puff and the nexts icceeding puii.

the ejector-[actionissubst'antially ineffective and the gases, are permitted substantially freeexitfthrough the passage 15. The degree of ejector actionaccomplished, and the size of the discharge passage 15, may be so proportioned that theproper portion ofeach '5 a casing of rounded form, an exhaustconduit leading from an internal combustion engine puff of gases may be prevented exit at the instantof the puff and permitted exit between puffstoobtain a substantially-constanti flow of gases outwardlyrthrough the passage 15.

Referring now to Figures 3 and, hthereis shown a casing 18, the inner walls of which are preferably substantially circular, and

into which the gases from the-exhaustjpipe 10 are projected preferably,substantially tangentially,v Thewalls ofthe casing thereforecausethe gases projected thereinto to swirl around: as indicated by the arrows, the

gases tending in theirnioveinent to fly-outwardly in a radial direction due to centrifv ugal force. vThis movement of the gases tends to produce a reduction of pressure within the casing substantiallyat', the center of curvature of the walls thereof. At thecenterthe casing is provided with a dis-,

opening 19 istherefore reduced] The parts may be so; proportioned that a-portion of each ,made of the above invention t ter n 'tially balanced by discharge.

. It maybe here noted that theniufiier casings above described, and shown in Figures 1 2 and 3 are in 'o eration .ireferabl osi-' P l y P tioned fiat-wise or'hori zontal, that is so that the paths of the gases therethrough are substantiallyhorizontal. In this manner the discharge openings 13, 15 and 19 open from the bottoms'of the casings. This position ing provides for the conyenientjpassingout through the: discharge passages of unburned gases which find their way into the muflier, casings, for example, when the, engine isturnedover without ignition. V v I From the above, it will be seen that there is herein provided apparatus which embodies ed to ineet the requirementsof practical usein a highly sat sfactory manner. As many possible embod ments may be changes, might be' nade in the V embodiment above set forth, it is to be understood that all. matter hereii beforeiset forth is to be in terpreted as illustrative and notina limiting sense. I

I claim as my invention: 1.,In muffler construction,

and directed-tangentially into said casing whereby gases thereinwill be whirled by the discharge from said conduit, said casing having a discharge port in injector relation to gases, the total cross-section of the discharge port from the casingand its in combination, 3 00 the same is adapt and a as many 7 relation to the entering gases being such that ,1

the tendency to increased discharge due to the discharge is constant andsubstantially uniform. 1

2. Inmufiler constructiomin combination, a substantially circular casing an exhaust conduit directed tangentially into said casing whereby gases therein willbe whirled,

said casing being formed to provide a single discharge port adjacent said conduitand so.

positioned that incoming gases will retardthe 3. In mufier construction, in combination,

a substantially circular casing, an exhaust conduit directed tangentially into said casing whereby gases therein will be whirled," said casing being formed to provide a single dischargeport-adjacent said conduit and so positioned that incoming gases will retard the discharge, and said casing, being shaped and f increased pressure in the casing s substannjector act on whereby mounted to permit unburned gas therein freely to flow out.

4. In muffler construction, in combination, a casing, an exhaust conduit directed into said casing in a tangential direction whereby gases therein will be whirled, and means forming a discharge port about the end of said conduit and so shaped and so related thereto that injector action of the incoming gases will retard the discharge of gases.

5. In muffler construction, in combination, a casing, an exhaust conduit directed. into said casing in a tangential direction whereby gases therein will be whirled, and means forming a discharge port about the end of said conduit and so shaped and so related thereto that injector action of the incoming gases will retard the discharge of gases, the crosssection of said discharge opening being 1;, proportioned to permit the discharge to be continued while the exhaust is entering the casing.

6. In mulliler construction, in combination, a casing, an exhaust conduit positioned to discharge directly into said casing, said cas ing being shaped to form a curved wall against which the entering gas is directed and a discharge port about the end oi said conduit and independent of the path of the entering gas of substantially less diameter than that of the casing and so related thereto and of such cross-section that injector action of incoming gases will tend to retard the discharge to such extent as will compensate and substantially balance the tendency to increased discharge due to access of pressure from the incoming gases.

7. In muffler construction, in combination, a casing of rounded form, and an exhaust conduit directed into said casing in a tangential direction, said casing being formed to provide a discharge opening about the end of said conduit and in injector relation there to and out of the path of travel of the incoming gases, whereby the discharge of gases may be continuous and substantially uniform.

8. In muliier construction, in combination, casing of rounded form, an exhaust conduit directed tangentially into said casing, and

a means forming an outlet port about the end of said exhaust conduit in position to permit outgoing gases to be discharged independently of the path of travel of incoming gases and to be retarded by injector action of the latter, said casing being shaped and mounted to permit unburned gas therein freely to flow out.

In testimony whereof, I have signed my name to this specification this 27th day of M May,1924. I

ROBERT S. BLAIR. 

